As of today 2018 June, is there an Android wallet that lets you do a dash private send? I know coinomi has Dash, but it doesn't have the privacy send features.
No. Currently, the PrivateSend feature is only available at the Dash Core wallet (desktop). The next protocol release (12.4), expected in the second half of 2018 will include deterministic masternode lists, that will make it possible to implement PrivateSend in mobile wallets.